Power-operated machine tools have a rotating spindle and a workholding chuck. Various tools are received in a tool holder for mounting on a rotating spindle for drilling, reaming and other metal removing operations. These tools may have a long shank with an end receivable centrally in the tool holder and the cutting end may project some distance from the tool holder for deep drilling or reaming.
It is extremely difficult, if not impossible, to produce a tool with a long shank in which when rotating the cutting end does not have what is termed "run-out", that is, orbital or rotational movement at the cutting end because it is not on dead-center with the axis of rotation of the machine tool spindle. The present invention is directed to a tool holder design which provides compensation for this "run-out" and allows adjustment of the cutting end of the tool to an "on-center" position with little or no run-out.